IGF has the longer half life; therefore it's used as a screening test for acromegaly. GH has a short halflife so it's not the first test in screening.
IGF-1 is elevated in insulin resistance.

[[Encodrinology MCQ discussion#Growth Hormone disorder diagnosis and investigation]]
| Hormone Type | Site of secretion | Mechanism of action | Receptor Sites | Effects | Transport | Pattern of secretion |
|---|---|---|---|---|---|---|
| Peptide | Somatotroph cells of Anterior pituitary | Mainly acts on the liver to stimulate IGF-1 production, Acts directly and indirectly on epiphyseal bone | cell membrane receptor (esp. on hepatocytes). Receptor defects cause Laron dwarfism | Pulsatile (10 pulses per day, 90 minutes each -easy to miss in a spot sample) | ||
Stimulation: GHRH, Ghrelin
GH secretion peaks in early puberty
[!Tip] Mnemonic: GH affects all macromolecules - makes things grow
- Lipids -> increase lipolysis
- Proteins -> Increased protein synthesis
- Electrolytes -> Phosphate, salt and water retention
- Bone -> Epiphyseal bone growth
[[Encodrinology MCQ discussion#Growth Hormone disorder diagnosis and investigation|Diagnosis and Investigation of GH disorders]]
As commonest cause if somatotroph adenoma:
acreomegaly is associated with symptoms caused by pressure effect of adenoma:
Level of secretion of prolantin due to a given stimulus proportional to background hyperplasia of lactotrophs which is driven by oestrogen.
Prolactin secretion by lactotrophs is under tonic inhibition of dopamine (which acts on D2 receptors of the lactotrophs) secreted by the tuberoinfundibular pathway, originating in the arcuate nucleus of the hypothalamus.
Hyperprolactinaemia causes amenorrhoea
StatPearls prolactin
#2023GM Q24
[!TIP] Summary
A saprophytic organism that can usually presents as acute pneumonia but can cause chronic / recurring infection and involve any organ(local or disseminated).
Resistant to many antibiotics. Usually infects people with some comorbidity like DM.

Gram negative (negative - pink); Characteristic bipolar safety-pin appearance.
An environmental organism. (as opposed to zoonosis - it's a saprophyte)
followed by months of coamoxiclav / cotrimoxazole.
Similar to community acquired pneumonia +/- sepsis
In endemic regions, melioidosis should be routinely considered part of the differential diagnosis of acute or chronic pneumonia, ulcerated or purulent skin lesions, undifferentiated sepsis, and prostatic abscesses; it should also be suspected as a potential cause of bone or joint infection, encephalomyelitis involving the brainstem and/or spinal cord, and cerebral or visceral abscesses.
#2023BSQ Q3
#2023GM Q28
Polygenic inheritance pattern - genes but possible env factor interact to produce Parkinson's disease.
Parkinson's disease ≠Parkinsonian syndromes.
Pathogensis: Loss of dopaminergic neurons in past compacta of substantia nigra of midbrain which project to the striatum of the basal ganglia. 70% loss has occured when symptoms appear.
Pathology: Lewy bodies (neuronal inclusions) seen
Symptoms Usually more prominent on one side.
| Main motor symptoms | Others |
| --------------------------- | --------------------------------------- |
| Tremmor, akinesia, ridigity | Writing becomes smaller, mask like face |
| Drug | Mechanism | Clinical context | Side effects |
|---|---|---|---|
| Levodopa | Dopamine - crosses BBB | most effect drug | Choreiform movements, wearing off and on/off effects with prolonged Rx |
| ==Benserazide== (cobeneldopa) | |||
| ==carbidopa== (cocareldopa) | ==Both== are dopa decarboxylase inhibitors | combined with levodopa to reduce side effects | |
| Dopamine agonists | |||
| Selegiline / rasagiline | MAO - inhibit dopamine breakdown | ||
| Amantadine | Enhances dopamine release | Modest effect - used in advanced disease | |
| Antimuscarinics | used to reduce tremmor in younger patients as confusion can occur in older patients | ||
| Entacapone | Catachol-O-methyltransferase inhibitor | Prolongs levodopa action - used to manage on/off phenomena | |
| Apomorphine | Potent dopamine agonist - short acting | used as rescue therapy during an 'off' episode | |
| Deep brain stimulation is promising! |
#2023BSQ Q37
Secreted by parietal cells under regulation of
Functions of gastric acid:
3 phases of secretion
Fundus and body have gastric glands which have chief cells at their bases. Chief cells secrete pepsinogen which gets activated to pepsin in the low pH (<4) environment of the stomach. (Chief cells also produce gastric lipase)
[!INFO] Definition of a Paraprotein
Very high levels of a single immunoglobulin is called a paraprotein or M protein (M for monoclonal). Caused by monoclonal proliferation of plasma cells
The cause for the plasma cell proliferation could be
Most premalignant disorders in medicine have limited clinical consequence until malignant transformation occurs. In contrast, premalignant clonal expansion of plasma cells can result in disabling or fatal disease related to the secreted immunoglobulin, termed monoclonal gammopathy of clinical significance
The paraprotein can consist of
Clinical manifestations of paraproteinemias
Many causes: See UpToDate table "Disorders associated with the presence of a monoclonal gammopathy"
(Youtube) -
aka Lymphoplasmacytic lymphoma
blood cancer affecting B lymphocytes.
Commoner in males > 50 years old. MYD88 gene mutation + CXCR4 gene (these are not inherited defects)
High numbers in bone marrow ->high IgM -> Blood becomes extremely thick.
IgM is the largest of the antibody types -> "macroglobin"
Signs and Symptoms : damage to small blood vessels - nose and gums.
Retina can be involved - impaired vision.
RBC crowded out of bone marrow -> anaemia
Tingling in exremeties
Ig accumulates in LN, spleen, liver. -> hepatosplenomegaly
If asymptomatic -> watchful waiting
If thick block -> plasmapheresis
Rituximab + other agents